gl^g ON ELECTRICAL CHARGES AND DISCHARGES. 



Certificates from Messrs. J. Haynes and Son, Westmoreland 

 Buildings; John Kelly, Hooper-Street, Clerkenwell; John 

 Foster, Author Street, St.Luke's; and William Foster, Author 

 Street, St. Luke's, states, that they have been in the habit of 

 using Mr. Turrell's nnififles for upwards of twelve months, 

 that they are greatly superior to any they have hitherto been 

 able to procure; and that it is their opinion their durability 

 may be completely attributed to his improved method of 

 moulding them. 



VI. 



Considerations on the State in which a Stratum of nonconduct- 

 ing Matter must be, when interposed between Txco Surfaces 

 endued with opposite Electricities : by A. Avogadro, Cor- 

 responding Member of the Academy of Sciences at Turin*, 



SECTION I. 



State of anon- A HOSE learned natural philosophers, who have lately 

 conductor be- gtudied with so much success the mechanism of the forces, 

 ductorsnot'suf- ^^^^ electricities of the same or opposite kinds exert on each 

 ficiently exa- other, either in conducting substances, or through noncon- 

 aiined. ductors, have not paid equal attention to the facts, that may 



lead us to some knowledge of the state of the insulating 

 substancef through which these forces act; particularly when 

 it is interposed between two electricities of opposite kinds, 

 that mutually support each other by their attraction. Yet 

 ii such facts exist, they might lead us to consequences of 

 great importance to the theory of electricity, In reality the 

 circumstances I have just mentioned, the interposition of an 

 insulating stratum between two bodies endued with opposite 

 electricities, is of great extent in electrical phenomena : it 

 MOt only takes place with respect to substances made to ap- 

 proach each other expressly for this purpose, and in charg- 



• Journal de Phisique, vol. LXIII, p. 450. 



•f In this paper 1 employ the term insulating as synonimous with what 

 Is commonly called nonconducting , or electric per se, 



ins 



